By using a novel technique of extraesophageal saline injection (ESI),the esophagus is to be separate from the adjacent organs.The space between esophagus and adjacent organs can be detected by endoscopic ultrasonography enhanced with ESI.Therefore, ESI plus with EUS is to be differentiate between T3 and T4 stage esophageal squamous cell carcinoma (ESCC). The objective of this Phase Ⅰstudy is to confirm the safety and efficacy of ESI.